Control of steam-turbine-driven boiler-feed pumps.



c. R. LANG, CONTROL OF STEAM TURBINE DRIVEN BOILER FEED PUMPS. APPLICATION FILED JUNE 3, 1912.

2 SHEETS-SHEET 1.

zwz Ewe? M MW Wm M Patnted Oct. 15,1912.

O.R.LANG. CONTROL OF STEAM TURBINE DRIVEN BOILER FEED PUMPS.

APPLICATION FILED FUNK 3, 1912.

Patented 0ct.15,1912.

1.641.492. To all mag concern: 1 i

(a 7 subject of the King of Great Britain-and Ireland residing at Cathcart,

newendauseful Improvements in the Control, of Steam-Turbine-Driven Boiler-Feed Pumps, of which the following is a specifeedt-anka fr j whgichit: is drawn by the lfiee d pump. q for fdisch argej ,into the boiler. pump tq the boiler, through the steam-pipe QOndensergrfromfihe condenser to the air i pp p, air .ump to .feed tank, and feed tank topfeedpump. The total amount of Water in thiscireuitis approximately con- 9 S.t,1,nt :any smalhwastage being. made up by auxiliaryfeed eand in large installations gg-"ljtlieg ca'pacityyof the feed tank bears a very small proportion to the quantity .ofwater in circulation so that a variation in the water level of the boilers,.without extra water he- 1 ing put intothe system, might easily empty the feed tank. Further, it.is characteristic of turbine driven feed pumps that, should the feed tank become empty and the pump to in consequencedraw air, the load on the turbine drivingthe pump becomes very small and its speed of rotation rapidly accelerates. Such turbine-driven pumps are generally fitted with a safety governor, which; under the above conditions, completely cuts off steam to the turbine and stops the pump. Before the pump can be started, the governor must be reset. This isan operation re p quiring a certain ,amount of time and; with water-tube boilers' with-"a. comparatively small quantity of contained .water, involves a dangerous delay. ."i

The objectof 'my present invention is to Be. it ,known. that I, CHARLES RUSSELL .-G*la-sgow,- Scot1and, have invented certain.

from; thelimain condensers is commonly dis- Y charged by the air pump intoa reservoir or uit isjthus established from the -feed.

jq'i heamain-engine, from the engine .to'the of the pipe in from the feed tank wi l l 'lS an equilibrium pipe connecting the of the yessel vwiith the top of the feed talk. The feed pump suction UNITED S dilating earner caries.

contract or STEAM-TURBINE-DRIVEN BOILER-FEED runes s'p i a of e ratemecioa'a 15,1912. Application aie June 3. 1912. Serial Nb. 701,292.

section, of a device according to my invention, the'float being located in a vessel connected with the feed tank. Fig. 2 shows a similar device but with the float located in a direct-contact feed heater which is on the suction side of the pump and the discharge side of the feed tank or hot well.

In bothfigures a is the boiler feed pump and b is the steam turbine which drives it. 5

0 is the suction to the pump and (Z the discharge.

e is the steam pipe by which the turbine is fed with steam and f is a stop valve on this pipe. This throttle valve 9 is also provided on this steam pipe and is actuated by the lever h which is connected by the link 7.: to

the lever mt This lever m is arranged to support the float.

My invention is not confined to any particular mechanism'for supporting the float, but a convenient mechanism isshown in Figs. 1 and 2. The mechanism is identical i these two figures but the float is shown only in Fig. 1.

. The float- 0 is suspended at the bottom of the link p which is pivoted to the levers q and 1? which are keyed respectively on the spindles s and t. The spindle .1? passes through the side of the vessel containing 35 speed of rotation of. the pump to 'aii e ictent List ,sufiicient to prevent its pumping water into the boilers.

In Fig. lathe float inclosed in the vessel 1) into which thefeed water can flow; by tway piper draws from the bottom 'of the vessel 11. f

In Fig. 2 the float is located in, the lower end of the direct-contact feed heater 2. The feed-pump suction pipe 0 draws from the bottom of this heater while thetfeed from the hot'well-isadmitted to the heater by the pipe 3. 4: is a steam connection whereby exhaust steamis admitted to the-heater for heating purf'oses.

If the normal speed of rotation of the turbine-pump shaft is above its critical velocity, that is the angular velocity at which excessive vibration occurs, the speed is reduced by the float mechanism to an extent which still keeps it above the critical velocity while preventing the generation of water pressure suflicient to deliver water into the boiler against the pressure therein. Vibration and risk of injury through the shaft rotating at its critical velocity are thus obviated.

My invention is not limited in its application to pumps driven direct by steam turbines but applies also in cases where the turbine drives the pump through speed-reduction gearing, and in such cases the critical velocity to be considered is that of the higher-velocity shaft, that is, the turbine shaft.

/ Having now particularly described my invention, what I claim as new and desire to secure by Letters Patent is v -1. In combination, a boiler, a rotary pump adapted to supply water to said boiler a steam turbine adapted to drive the said pump, a steam pipe adapted to conyey steam to the said turbine for the purpose of driving it,/a throttle valve on said steampipe, a float located in a vessel from .which the said pump draws its water, and means whereby said float can reduce the speed of rotation of said turbine, to a velocity below that necessary to deliver water into said boiler against the' pressure therein.

' 2. In combination, a boiler, a rotary pump adapted to supply water to said boiler, a steam turbine adapted to drive the said pump, a steam pipe adapted to convey steam to the said turbine for the purpose of driving it, a throttle valve on said steam pipe, a

float located in a vessel from which the said pump draws its water, and means whereby said float can operate said throttle valve to reduce the speed of rotation of said turbine 4 pipe, a float located in a vessel from which the said pump draws its water and which is connected to and supplied witlrwater from the said feed tank, and meanswhereby said float can operate said throttle valve to reduce the speed of rotation of said turbine to a velocity below that necessary to deliver water into said boiler against the pressure therein.

I, In combination, a boiler, a feed tank adapted to contain feed water fOlflStLld boiler, a rotary pump adapted to supply water to said boiler, a steam turbine adapted to drive said pump, steam pipe adapted to convey steam to said turbine for the purpose of drivin :git, a throttle valve'on'said steam pipe, a bat located in a vessel from which the said pump draws itslwaterfland which is con ne'cted to and supplied with water from the said feed tank,.and means whereby said float can operate said throttle valve to reduce the s eed of rotation of said turbine to a velocityelow that necessary to deliver water into said boiler against; the

pressure therein, and above the critical: ve-

locity of. the said turbine. In testimony whereof,I afiiX my signature in presence of two witnesses. f

CHARLES RUSSELL LANG. Witnesses: l V

' ROBERT MORRISON Nnnisolv,

- GEO. H. FREEMAN. 

